The present invention relates to a milling cutter having a plurality of reversible cutting plates arranged along the circumferential side of a cylindrical supporting body in rows in the longitudinal direction of the body. At least one of the rows terminates at the frontal face of the supporting body with a reversible face cutting plate which has a cutting edge for cutting both at the frontal face and circumferential side of the supporting body. The cutter further includes at least one cassette for accommodating at least one reversible face cutting plate. The cassette is releasably held in an essentially radial recess in the supporting body and rests against an abutment face which secures the radial position of the cassette.
Milling cutters employing reversible cutting plates, and used, in particular, for rough cutting with larger cutting depths, should work with the greatest possible cutting performance with good economy and service life. For structural reasons, the longitudinal rows of reversible cutting plates disposed at the circumference of the supporting body are offset with respect to one another such that a total overlap results in the logitudinal direction of the supporting body. In such embodiments, the number of reversible face cutting plates (i.e., those plates that cut at both the frontal face and circumferential side of the supporting body) is generally less than the total number of rows of cutting plates. In most cases the total number of rows is twice the number of the reversible face cutting plates which are under particularly great stress from the cutting forces occurring during the cutting process and from thermal stresses connected therewith.
A breakage in a reversible face cutting plate often extends across the corner of the cutting edge of the cutting plate and generally brings about substantial damage to the supporting body which, under certain circumstances, prevents its further use. Therefore, numerous attempts have been made to protect as best as possible the relatively expensive supporting body of a milling cutter against damage by suitable design and arrangement of their coacting components.
Swiss Patent No. 564,998 and German Offenlegungsschrift (Patent Application published without examination) No. 2,603,735 disclose milling cutters in which reversible cutting plates are supported and held in a supporting body by cassettes. These cassettes, which each exchangeably hold one reversible cutting plate, are of essentially cylindrical design and are held in correspondingly shaped, essentially radially oriented recesses in the supporting body.
A drawback of these known embodiments is that in order to provide a sufficiently precise positioning of the reversible cutting plates in the supporting body, they require relatively complicated additional elements such as a central abutment as in the above noted Swiss patent, or a set screw which cooperates with an abutment cylinder as in the above noted German patent application.
Another disadvantage of the known prior art milling cutters is that the cylindrically shaped cassettes, due to their geometrical shape, only provide sufficient support for the associated reversible face cutting plate in its greatly endangered corner region if the supporting body projects as far as possible in the direction toward the reversible face cutting plate. The result is that the cassettes holding the reversible face cutting plates are flush with the frontal face of the supporting body. The supporting body, because it axially lies slightly behind the frontal face cutting edge of the reversible face cutting plates, can easily be damaged.
A further drawback of the known embodiments is that, due to the arrangement and configuration of the cassettes, as well as the projecting design of the supporting body, the use of differently shaped reversible face cutting plates is not possible unless additional measures are taken.